The following individuals read the manuscript and offered many helpful suggestions: Mr. R. L. Downing, Mr. C. W. Severinghaus, Mr. J. M. Peek, Dr. C. T. Cushwa, Mr. M. H. Stenlund, and Dr. R. R. Ream. LITERATURE CITED Crisler, Lois. 1956. Observations of wolves hunting caribou. J. Mammal. 37: 337-346. Downie, N. M., and Heath, R. W. 1959. Basic statistical methods. 289 p. New York: Harper and Bros. Erickson, A. B., Gunvalson, V. E., Stenlund, M. H., Burcalow, D. W., and Blankenship, L. H. 1961. The white-tailed deer of Minnesota. Minn. Dep. Conserv. Tech. Bull. 5, 64 p. Gilbert, F. F. 1966. Aging white-tailed deer by annuli in the cementum of the first incisor. J. Wildl. Manage. 30: 200-202. Kelsall, J. P. 1969. Structural adaptations of moose and deer for snow. J. Mammal. 50: 302-310. Klein, D. R., and Olson, S. T. 1960. Natural mortality patterns of deer in southeast Alaska. J. Wildl. Manage. 24: 80-88. Kuehn, D. W. 1970. An evaluation of the wear method as a criterion for aging white-tailed deer. M.S. Thesis., Univ. Minn. Latham, R. M. 1950. Pennsylvania's deer problem. Penn. Game News, Spec. Issue 1. (Cited from: Allen, D. L. 1962. Our Wildlife Legacy.) Maguire, H. F., and Severinghaus, C. W. 1954. Wariness as an influence on age composition of white-tailed deer killed by hunters. N. Y. Fish and Game J. 1: 98-109. Mech, L. D. 1966a. The wolves of Isle Royale. U.S. Nat. Park Serv. Fauna Ser. 7, 210 p. Mech, L. D. 1966b. Hunting behavior of timber wolves in Minnesota. J. Mammal. 47: 347-348. Mech, L. D. 1970. The wolf: the ecology and behavior of an endangered species. 389 p. New York: Natural History Press, Doubleday. Mech, L. D., Frenzel, L. D., Jr., Karns, P. D., and Kuehn, D. W. 1970. Mandibular dental anomalies in white-tailed deer from Minnesota. J. Mammal. 51: 804-806. Murie, A. 1944. The wolves of Mount McKinley. U.S. Nat. Park Serv. Fauna Ser. 5, 238 p. Pimlott, D. H., Shannon, J. A., and Kolenosky, G. B. 1969. The ecology of the timber wolf in Algonquin Provincial Park. Ont. Dep. Lands and Forests Res. Rep. (Wildl.) 87, 92 p. Ryel, L. A., Fay, L. D., and Van Etten, R. C. 1961. Validity of age determination in Michigan deer. Mich. Acad. Sci., Art, and Letters 46: 289-316. Severinghaus, C. W. 1949. Tooth development and wear as criteria of age in white-tailed deer. J. Wildl. Manage. 13: 195-216. Severinghaus, C. W. 1955. P. R. Rep. W-28-R-9: Job 1A, April 13, 1955. Shaw, S. P. 1951. The effect of insufficient harvests on an island deer herd. N.E. Wildl. Conf. (Mimeo). Siegel, S. 1956. Non-parametric statistics for the behavioral sciences. 312 p. New York: McGraw-Hill. Stenlund, M. H. 1955. A field study of the timber wolf (_Canis lupus_) on the Superior National Forest, Minnesota. Minn. Dep. Conserv. Tech. Bull. 4, 55 p. THE EFFECT OF SNOW CONDITIONS ON THE VULNERABILITY OF WHITE-TAILED DEER TO WOLF PREDATION L. David Mech, L. D. Frenzel, Jr., and P. D. Karns